Really, no one should ever walk into Fringe mad scientist Walter Bishop's lab without passing by heaps and heaps of giant, flashing warnings. In a pinch, though, these simple posters should do the trick.

Christian Petersen is selling this series of posters based on various fringe sciences at his Etsy store. Some of the sciences are farther on the fringes than others, but any of these posters should be enough to make visitors think twice before entering your workspace.